PAK4 confers the malignance of cervical cancers and contributes to the cisplatin-resistance in cervical cancer cells via PI3K/AKT pathway.

Shu XR, Wu J, Sun H, Chi LQ, Wang JH - Diagn Pathol (2015)

Bottom Line:
Multiple protein or microRNA markers have been recognized to contribute to the progression and recurrence of cervical cancers.In addition, the PI3K/Akt pathway has been implicated in the PAK4-confered cisplatin resistance.And the PI3K/Akt inhibitor, LY294002, markedly deteriorated the cisplatin-mediated viability reduction of Hela or Caski cells, indicating the involvement of PI3K/Akt pathway in the cisplatin resistance in cervical cancer cells.

Background: Multiple protein or microRNA markers have been recognized to contribute to the progression and recurrence of cervical cancers. Particular those, which are associated with the chemo- or radio-resistance of cervical cancers, have been proposed to be promising and to facilitate the definition for cervical cancer treatment options.

Methods: This study was designed to explore the potential prognosis value of p21-activated kinase (PAK)-4 in cervical cancer, via the Kaplan-Meier analysis, log-rank test and Cox regression analysis, and then to investigate the regulatory role of PAK4 in the cisplatin resistance in cervical cancer cells, via the strategies of both PAK4 overexpression and PAK4 knockout.

Results: It was demonstrated that PAK4 was upregulated in cervical cancer tissues, in an association with the cancer's malignance variables such as FIGO stage, lymph node or distant metastasis and the poor histological grade. The high PAK4 expression was also independently associated with poor prognosis to cervical cancer patients. Moreover, PAK4 confers cisplatin resistance in cervical cancer Hela or Caski cells. In addition, the PI3K/Akt pathway has been implicated in the PAK4-confered cisplatin resistance. And the PI3K/Akt inhibitor, LY294002, markedly deteriorated the cisplatin-mediated viability reduction of Hela or Caski cells, indicating the involvement of PI3K/Akt pathway in the cisplatin resistance in cervical cancer cells.

Conclusion: This study has confirmed the significant prognostic role of PAK4 level in cervical cancer patients and has recognized the regulatory role in cervical cancer progression. Moreover, our study has indicated that PAK4 also confers the chemoresistance of cervical cancer cells in a PI3K/Akt-dependent way. Thus, our study indicates PAK4 as a promising marker for cervical cancer treatment.

Fig4: PI3K/Akt-dependence of the PAK4-mediated cisplatin resistance in cervical cancer cells. a and b: Phosphorylation of PI3K/Akt in Hela (a) and CaSki (b) cells, which were treated with 5 (for Hela cells) or 10 μM (for CaSki cells) cisplatin and with 10 or 20 nM (for Hela cells), or with 15 or 30 nM (for Caski cells), LY294002; c and d: Influence of the treatment with 10 or 20 nM LY294002 in Hela cells, or the treatment with 15 or 30 nM LY294002 in Caski cells on the cisplatin-mediated (5 μM for Hela cells or 10 μM for CaSki cells) viability reduction for 12, 24 or 48 h. Experiments were repeated in triplicate independently. *P < 0.05, **P < 0.01 or ns: no significance

Mentions:
To explore the mechanism underlying PAK4-induced cisplatin resistance in cervical cancer cells, we examined the activation of PI3K/Akt pathway in the cisplatin-treated Hela and Caski cells, with or without the transfection with siRNA-PAK4 or siRNA-Con. The western blotting results demonstrated that the PAK4 level was not markedly regulated by the 5 μM cisplatin treatment in both cell lines, whereas the phospholylated PAK4 was promoted by the 5 μM cisplatin treatment (Column 1 and 2, Fig. 4a and b). However, such both PAK4 and p-PAK4 was significantly downregulated by the transfection with siRNA-PAK4 (Column 3 and 4, Fig. 4a and b). Moreover, the phosphorylated AKT was significantly promoted by the cisplatin treatment in Hela cells. However, the promotion to the phosphorylated AKT was also inhibited by the transfection with 50 nM siRNA-PAK4, compared with the transfection with 50 nM siRNA-Con (Fig. 4a). And such promotion to the phosphorylated AKT and the inhibition by siRNA-PAK4 were also confirmed in Caski cells (Fig. 4b). To investigate the role of AKT phosphorylation in the cisplatin resistance in cervical cancer cells, we then measured the viability of cisplatin-treated Hela and Caski cells, in the presence of PI3K/Akt inhibitor, LY294002. Figure 4c demonstrated that there was no significant regulation on the viability of Hela cells by the treatment with 10 or 20 nM LY294002. However, the LY294002 treatment markedly deteriorated the cisplatin-mediated viability reduction of Hela cells with a concentration of 10 (p < 0.05) or 20 nM (p < 0.01), dose-dependently (p < 0.05). And such effect was repeated in Caski cells, either concentration of 15 or 30 nM LY294002 markedly aggravated the cellular viability reduction (p < 0.05 or p < 0.01, Fig. 4d), dose-dependently (p < 0.05). Thus, our results confirmed the involvement of PI3K/Akt-dependent pathway in the PAK4-confered cisplatin resistance.Fig. 4

Fig4: PI3K/Akt-dependence of the PAK4-mediated cisplatin resistance in cervical cancer cells. a and b: Phosphorylation of PI3K/Akt in Hela (a) and CaSki (b) cells, which were treated with 5 (for Hela cells) or 10 μM (for CaSki cells) cisplatin and with 10 or 20 nM (for Hela cells), or with 15 or 30 nM (for Caski cells), LY294002; c and d: Influence of the treatment with 10 or 20 nM LY294002 in Hela cells, or the treatment with 15 or 30 nM LY294002 in Caski cells on the cisplatin-mediated (5 μM for Hela cells or 10 μM for CaSki cells) viability reduction for 12, 24 or 48 h. Experiments were repeated in triplicate independently. *P < 0.05, **P < 0.01 or ns: no significance

Mentions:
To explore the mechanism underlying PAK4-induced cisplatin resistance in cervical cancer cells, we examined the activation of PI3K/Akt pathway in the cisplatin-treated Hela and Caski cells, with or without the transfection with siRNA-PAK4 or siRNA-Con. The western blotting results demonstrated that the PAK4 level was not markedly regulated by the 5 μM cisplatin treatment in both cell lines, whereas the phospholylated PAK4 was promoted by the 5 μM cisplatin treatment (Column 1 and 2, Fig. 4a and b). However, such both PAK4 and p-PAK4 was significantly downregulated by the transfection with siRNA-PAK4 (Column 3 and 4, Fig. 4a and b). Moreover, the phosphorylated AKT was significantly promoted by the cisplatin treatment in Hela cells. However, the promotion to the phosphorylated AKT was also inhibited by the transfection with 50 nM siRNA-PAK4, compared with the transfection with 50 nM siRNA-Con (Fig. 4a). And such promotion to the phosphorylated AKT and the inhibition by siRNA-PAK4 were also confirmed in Caski cells (Fig. 4b). To investigate the role of AKT phosphorylation in the cisplatin resistance in cervical cancer cells, we then measured the viability of cisplatin-treated Hela and Caski cells, in the presence of PI3K/Akt inhibitor, LY294002. Figure 4c demonstrated that there was no significant regulation on the viability of Hela cells by the treatment with 10 or 20 nM LY294002. However, the LY294002 treatment markedly deteriorated the cisplatin-mediated viability reduction of Hela cells with a concentration of 10 (p < 0.05) or 20 nM (p < 0.01), dose-dependently (p < 0.05). And such effect was repeated in Caski cells, either concentration of 15 or 30 nM LY294002 markedly aggravated the cellular viability reduction (p < 0.05 or p < 0.01, Fig. 4d), dose-dependently (p < 0.05). Thus, our results confirmed the involvement of PI3K/Akt-dependent pathway in the PAK4-confered cisplatin resistance.Fig. 4

Bottom Line:
Multiple protein or microRNA markers have been recognized to contribute to the progression and recurrence of cervical cancers.In addition, the PI3K/Akt pathway has been implicated in the PAK4-confered cisplatin resistance.And the PI3K/Akt inhibitor, LY294002, markedly deteriorated the cisplatin-mediated viability reduction of Hela or Caski cells, indicating the involvement of PI3K/Akt pathway in the cisplatin resistance in cervical cancer cells.

Background: Multiple protein or microRNA markers have been recognized to contribute to the progression and recurrence of cervical cancers. Particular those, which are associated with the chemo- or radio-resistance of cervical cancers, have been proposed to be promising and to facilitate the definition for cervical cancer treatment options.

Methods: This study was designed to explore the potential prognosis value of p21-activated kinase (PAK)-4 in cervical cancer, via the Kaplan-Meier analysis, log-rank test and Cox regression analysis, and then to investigate the regulatory role of PAK4 in the cisplatin resistance in cervical cancer cells, via the strategies of both PAK4 overexpression and PAK4 knockout.

Results: It was demonstrated that PAK4 was upregulated in cervical cancer tissues, in an association with the cancer's malignance variables such as FIGO stage, lymph node or distant metastasis and the poor histological grade. The high PAK4 expression was also independently associated with poor prognosis to cervical cancer patients. Moreover, PAK4 confers cisplatin resistance in cervical cancer Hela or Caski cells. In addition, the PI3K/Akt pathway has been implicated in the PAK4-confered cisplatin resistance. And the PI3K/Akt inhibitor, LY294002, markedly deteriorated the cisplatin-mediated viability reduction of Hela or Caski cells, indicating the involvement of PI3K/Akt pathway in the cisplatin resistance in cervical cancer cells.

Conclusion: This study has confirmed the significant prognostic role of PAK4 level in cervical cancer patients and has recognized the regulatory role in cervical cancer progression. Moreover, our study has indicated that PAK4 also confers the chemoresistance of cervical cancer cells in a PI3K/Akt-dependent way. Thus, our study indicates PAK4 as a promising marker for cervical cancer treatment.